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The carbon cycle is the cycle of carbon on our earth's surface. Plants trap co2 when they photosynthesize and breathe out oxygen. Animals eat the plants. They then breathe out the co2 and consume oxygen. this puts the co2 back into the atmosphere for more plants to absorb etc. This pattern runs in a cycle which is called the carbon cycle. Biomass is part of this cycle because the carbon in the plants came from the air not from the ground. The most common type of biofuel is ethanol. Ethanol is a type of alcohol that is formed with yeast. Ethanol could be a substitute for petroleum and gasoline in cars. Most ethanol, right now is made from corn because it is easy to grow. However corn takes a lot of energy to make ethanol. That means more Co2 into the atmosphere and more global warming. In brazil they make ethanol from sugarcane with much better results. One acre of sugarcane can produce up to 2,500 litres of ethanol compared to corn which makes only 1,500 litres per acre. There’s another problem with corn as well. When power companies compete with food companies for corn the price of corn goes up which in turn causes other many other foods to go up in price. This could increase the danger of worldwide food shortages. And even if we used all the corn in the US to make ethanol it would still only supply about 13% of our energy needs. Finally making corn based ethanol uses large amounts of water, taking about 15 litres of water to make 3.5 litres of ethanol. Water is a limited and shrinking resource in the world today.
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